Correctional facilities utilize communication systems that allow facility residents the ability to make voice and video calls, where these calls are subject to various conditions. These communication systems also provide the ability for administrators of the correctional facility to record the voice and video calls made by residents. These recordings of voice and video calls may be made according to a variety of rules that allow options such as recording calls made to specific telephone numbers, recording calls made by certain residents, recording calls made using specific devices, or recording calls that are processed by the communication system.
Recordings of resident voice and video calls may be monitored by authorities in order to determine information of interest, including information regarding continuing, past or planned criminal activities. The communication system may provide a variety of tools for detecting prohibited behavior, such as the participation of unauthorized individuals in a resident's call. These voice and video call recordings may also be stored for later investigation. In some situations, a recording may be deemed of evidentiary importance. For instance, a prosecutor may determine that a recorded call of an inmate may be used as evidence of criminal activity. In order to facilitate the use of recorded voice and video calls in this manner, it is desirable for the generated recordings to be admissible as evidence in a court of law.
When being used as evidence in a court of law, it is preferred that the authenticity of recorded calls can be established within requirements for admissibility of evidence. For tangible evidence (e.g., a weapon, an item of clothing, collected body fluids), accepted practices exist for establishing the authenticity and preserving a “chain of custody” of the evidence such that evidentiary requirements for admissibility can be proven according to the applicable laws and regulations. In general, each step of handling and storing an item of tangible evidence, from the point of collection of the evidence up to the proffer of the evidence in a courtroom, must be attested to by a witness. In a criminal matter, an authenticating witness is typically a police officer, a detective, a crime scene investigator, or a laboratory technician. When an item of tangible evidence in a criminal matter is not being actively used, it is typically placed in a sealed physical container and stored to an evidence storage facility (e.g., evidence locker). The physical container is typically identified, dated, and secured in a fashion that is intended to show that no tampering of the evidence took place during its storage. Various measures may be implemented for controlling and documenting access to stored evidence.
As with traditional tangible evidence, the issue of authentication must be addressed when proffering audio and video recordings of calls as evidence in a court setting. However, establishing the authenticity of a voice or video call recording presents certain difficulties that are not present when establishing the authenticity of tangible evidence. One such difficulty is establishing that the recording is an authentic reproduction of the monitored call and that the original recording has not been altered. Audio data, especially digital audio files, can be modified in ways that may be very difficult to detect. For example, recordings are typically stored to a file having a standard audio file format, such as a WAV or an AU audio file format. A variety of tools are freely available for editing such well-known file formats, providing an increased risk of an audio recording using one of these formats being edited in some way. The ability to record video has proliferated with the spread of portable devices capable of recording video has resulted in a similar spread of common filed formats and widely available tools capable of sophisticated video editing. The problematic nature of such file formats is increased further by legal requirements obligating criminal prosecutors to share important evidence with defendants in criminal proceedings. With multiple versions of the same recording at large, establishing whether an audio or video recording is an unaltered copy of the original call becomes increasingly important.
Another shortcoming of certain audio and video file formats is the lack of a capability, provided within the file itself, to establish the authenticity of the recorded information (i.e., to establish that the original recorded audio and/or video data has not been altered). Certain file formats provide the ability to specify additional information about the audio and/or video data in an associated “header.” A header may be used to provide additional information regarding the contents of the file. However, nothing prevents the editing of the header information and no capability is provided for establishing that the header information has not been modified.
These evidentiary requirements are not unique to scenarios where voice or video call recording made by correctional facilities are generated for use in a criminal setting. The need to authenticate an audio or video recording may arise in a variety of contexts. For instance, establishing the authenticity of a recording of a financial or legal transaction that is conducted at least in part via telephone or videoconference.